Gamma Knife Radiosurgery for Treatment of Essential Tremor

August 27, 2010

Essential tremor (ET) is the most common type of movement disorder, affecting approximate­ly four out of 1000 people, and is significantly more common, though less recognized, than Parkinson’s disease. ET affects men and women equally and is inherited as an autosomal-dominant condition in about 60 percent of cases.

Although often referred to as benign essen­tial tremor, it is hardly benign in patients who may not be able to write legibly, hold a glass of water or use a knife and fork. ET is primarily an action tremor of the upper extremities but may involve resting tremor of the head and neck and/or lower jaw, and also tremor of the voice. The latter may be so severe that speech becomes unintelligible.

Medication and surgical treatment options

Primidone and beta blockers are useful in re­ducing tremor in the early stages of ET, but as the tremor progresses, medical management often becomes less effective or side effects can prevent the use of adequate doses of medication. ET pa­tients then are candidates for surgical or radiosur­gical treatment.

The mainstay of the surgical treatment of ET is deep brain stimulation (DBS), in which an electrode is implanted in the ventral inter­mediate nucleus (VIM) of the thalamus. Neurosurgeons Peter Nora, M.D., and Ryder Gwinn, M.D., have been implant­ing DBS electrodes at Swedish Medical Center for several years. The treatment is effective, but it requires implantation of permanent hardware (wires and batteries) into the brain and chest wall. Patients who take anticoagulants or have severe cardio­vascular disease are not suitable candidates for DBS. These patients, however, may be candidates for radiosurgical treatment.

A new option for difficult-to-treat patients

A Gamma Knife® device is used to fo­cus high-energy gamma rays precisely on the VIM in a single outpatient treatment. This results in the death of the brain cells that generate ET. We recently published our experience in the radiosurgical treat­ment of more than 200 patients with ET. More than 80 percent of the treated pa­tients showed significant reduction in tremor, including nearly 50 percent who were entirely free of tremor. Patients could write legibly, drink without spilling and, in general, perform activities of daily living with minimal or no disability (see figure). These results are comparable to the data published for the use of DBS in the treat­ment of ET. Follow-up MRI scans in these patients demonstrated the development of lesions of about 6 mm in diameter precisely located in the VIM thalamus. Eight percent of patients developed lesions which were larger than expected. These large lesions occasionally resulted in sensory loss, hemi­paresis or speech difficulty. In about half of these patients, the neurological symptoms recovered over time, so the permanent rate of complications was about 4 percent. At present we have not been able to identify what factors may predict the development of an excessively large lesion.

Gamma Knife radiosurgery offers a means for the treatment of ET that is safe and effective without the need for implant­ed hardware. The rate of tremor relief and the complications compare favorably with DBS. Radiosurgery can be offered to all pa­tients who are candidates for surgical treat­ment of ET, but it is particularly useful for patients who are not candidates for DBS.

Topics: Neuroscience


How does a patients age factor in?What is the waiting period for this treatment?
Margarita, Patients age is not a factor for GK for ET. Not sure what is meant by the "waiting period"? If it means the waiting period to have the procedure it is usually about a month. If it means the waiting period between the time the procedure is performed and the tremor decreases it is 2-4 months.
We would like to get more information on the treatment of Essential tremors, with out the DBS. We saw the program on TV about a procedure without surgery. The program showed the lady had no tremor after this procedurre. It was done like when you have a MRI. Sorry i don't the right name for the machine. Any info you can give would be very useful. Thank You.
J, you can find more information about Gamma Knife here: . To speak with someone at the Swedish Radiosurgery Center for more information or to schedule a consultation, please call 206-320-7130.
I have read about the radiosurgery option for essential tremor with great interest, and first saw the procedure referenced in an Alaska Airlines magazine when I was on a recent visit to the US.My husband and I, both US citizens, have retired in Mexico, but have family living in the Seattle area. My husband, who is 66, has a rather severe essential tremor, confined to his arms and hands. He is taking propanalol, but its effectiveness has diminished. He is not a candidate for DBS, as he takes an anticoagulant for atrial fibrillation. We do not have US health insurance, but he does have Medicare Parts A and B. Would radiosurgery be a possibility for him? Does Swedish accept Medicare assignment? We do not have a supplemental policy. Thank you for your attention and consideration.
Hi Karen,Gamma Knife Radiosurgery is an option for people with essential tremor who have other medical conditions. Blood thinning medication and atrial fibrillation are not contraindications for this treatment. Medicare routinely covers Gamma Knife treatment.
Erin, thank you so much for your speedy response. I'll talk this over with my husband and call the Center to determine our next steps. He is an artist and can no longer draw or paint because of his tremor. What a wonderful gift it would be to restore his steady hands.Karen Knapp
I have been declared a candidate for DMS. To cumbersome, scary.I don't like all the hardware
Our 17 yr old son has ET that is getting progressively worse. He was diagnosed at 2 yrs old by a pediatric neurologist, but we were pretty certain we already knew what it was because of a strong family history. Our primary care doctor doesn't believe it would be optimal to treat him with beta blockers because of his extensive involvement in athletics. Do you believe the benefits of the gamma knife procedure outweigh the risks for someone so young? We are very interested in trying to help our son overcome some of the limitations created by ET. If his shoe comes untied in the middle of a basketball game, he literally cannot re-tie it because of the tremor (obviously exacerbated by adrenaline). Thank you!
Treating young adults with essential tremor can be complex and one suggestion would be asking your primary care doctor for a referral to a movement disorder neurologist to assess your son�s condition. This subspecialty within neurology has the best knowledge regarding the pharmaceutical options for active youth prior to considering more aggressive treatments such as Deep Brain Stimulation (DBS) or the Gamma Knife. Gamma Knife is not generally recommended for young people, especially if he is a candidate for DBS, for a number of reasons. Please view the attached video for more information about the DBS procedure:
My mother has been diagnosed for Essential Tremor sincem12 years ago. she has been medicated, but the tremor is worse each year. She suffers from tremor in the hands, both hands, she shakes so strongly she cannot write, eat, hold cutlery, or do any precise movement with her hands. Also she trembles from the lower jaw, her voice and her speach are not intelligible, and she trembles from the head.She tends to avoid social meetings, and feels a great impediment in her normal active life, due to ET.we would like to know if she is suitable for DMS. Please let me know. Thank you very,much. Cecilia Blasquez.
Ms. Blasquez,Thank you for your question regarding essential tremor. You mentioned she has tried medications but her tremor continues to progress and she has difficulty with many tasks which is affecting her quality of life. She may certainly be a candidate for either Deep Brain Stimulation (DBS) or Gamma Knife Thalamotomy which are described in the links below. DBS link: link: a consultation with a neurosurgeon to discuss these options would be a possible next step. For more information regarding our program, please call us and we can help direct you to the appropriate physicians. 206-320-7187.
II have been diagnosed with ET by Dr. Manek , neurologist in Spokane. My tremor in hands and mouth has worsened in last fewmonths. I have heard of the gamma knife procedure. I have a pacemaker and am unable to have MRI. Also have A-fib and take warfarin. Do these problems make me ineligible for gamma knife treatment?We are leaving for England Aug 8 and will return Aug 30.
Elizabeth, our program manager is out of the office this week & will post a reponse next week.
Dear Ms. McManis,Having a pacemaker and being on warfarin are generally OK for Gamma Knife treatment. For patients with non-MRI compatible pacemakers, we use a Catscan instead of MRI. Please contact us if you have any questions or if you need additional information.
I live in the UK , and I suffer from familial tremor . I am also a 77 year old diabetic type 2 on insulin .I am healthy , and do a lot of walkingRecently I had a consultation at Southampton Hospital , after given 2 choices of treatment, I decided to have the Gamma Knife. I was wondering if this treatment would permamently cure the tremors on both of my hands .My predominant hand is the Right my Left hand is also affected , to a lesser degree . Is it possible to have the Gamma Knife on both sides of the brain ?Peter Eric Sammut6 October 2013
I have high hopes about this treatmentPeter Eric Sammut UK
Hi,I was diagnosed with et at the age of 30 am now 42 and is getting worse. My tremor is in my neck and has just started in my hands. Iam always asked by strangers what I have? I don't want to be drugged up and I don't want implants so gamma knife sounds perfect. This causes me so much embarrassment and I suffer from depression as a result of 12 years of this. I want treatment. How can I start? I live in Mississippi so would have to travel but it would be worth it. Thank You
Dear Mr. Mason,Thank you for message and we would be happy to discuss our program and talk to you about Gamma Knife thalamotomy for essential tremor. If you can give us a call at 206-320-7187, we can provide more details.
How does focused ultrasound, if approved for ET, compare to GK. In the trials it looks like they are having a good success rate.
Nick,Your question is a good one, but it is a hard comparison to make. With the gamma knife, the overall accuracy of the system is < 1 mm. If you would like more information about either procedure, please contact us at 206-320-7187.
Since his diagnosis of ET my 86 year young dad has taken various meds with diminishing effectiveness and increasingly problematic symptoms impacting quality of life. Amazingly, without any history of clinical depression, should he be concerned about the onset of depression as a short/long term side effect (i.e.,change in brain chemistry) of Gamma Knife treatment for his tremors?
My neurosurgeon told me it could be up to 6 months after Gamma Knife to know if it worked. Is this true?
Lorene, the Gamma Knife treatment takes 3-6 months before most patients begin to see the impact of the treatment and the progress continues for up to a year. Some patients comment that they begin to see changes shortly after treatment but the data suggests the norm is 3-6 months. If you would like to schedule a consultation or receive more info, please call 206/320-7187.
I was diagnosed with familial ET at 13 and now I am 18. I have tried medications but have not had any success. I am very interested in GKT and not DBS because of GKT does not require permeant hardware. I am young and want to see the world without having to worry about hardware malfunctioning. Is GKT an option for someone as young as me? Does insurance pay for this surgery? How does GKT compare to stereotactic thalamotomy.
I have had ET for over 15 years. I presently take 1,000 mg of Primidone daily. Without the Primidone, I cannot even eat as my hands tremble so violently. With the Primidone I am able to write and have perhaps 90% control. I also take warfarin for a-fib. Would I be a candidate for GK. Mike